This invention relates generally to techniques for fabricating semiconductor integrated circuits.
In a number of instances, during the manufacture of semiconductor integrated circuits, vias, trenches, or other openings may be formed in a substrate. It may then be desirable to fill those openings with a metal. Depending on the size of the openings, it may be difficult to induce the metal material to completely fill the opening. There may be a number of reasons for this. One possible explanation relates to the adverse affects of surface tension and capillary forces.
In some cases, a bubble or void tends to form within the metal filled via or trench. Thus, the presence of surface tension and capillary forces may result in a void which results in incomplete filling of the trench or via. This filled trench or via with a void is a low quality electrical contact and is called a pinched off trench or via.
Thus, there is a need for a way to improve the filling of openings with metal.